Thank you for taking the time to report this bug and helping to make Ubuntu better. Please try to obtain a valgrind log following the instructions at https://wiki.ubuntu.com/Valgrind and attach the file to the bug report. This will greatly help us in tracking down your problem.

(don't know why valgrind can't solve the path, but at least it should give a more explicative error, rather than "can't open nameofprogram".... i'm pretty sure in a old bug report i failed to fetch a valgrind log due to this, i changed the ubuntu wiki page, or would it be better to file a bug against valgrind?)

this problem not only happens while installing a plugn, but even while saving/executing command args for the project, after exporting into .jar, while closing eclipse itself, and god knows what else ... if necessary i can create other valgring .logs even for those cases... right now eclipse is a royal PITA to use

Looks like both logs were done on amd64 machines. Eclipse starts a new process on launch on that arch, which means that valgrind unfortunately didn't catch the error. You can force Eclipse to start the jvm in the same process instead of a new one by giving it the arguments "-vm /usr/lib/jvm/java-6-openjdk/jre/lib/amd64/server/". If you use a jvm other than openjdk, replace the directory argument by the one containing libjvm.so for your preferred jvm.

Please check if this is a duplicate of Bug 445009. It is about a SIGSEGV in libpango after clicking Cancel like in Comment #21 and the Red Hat upstream bug, but not about text fields like the Eclipse upstream bug seems to be.
In this bug, there is another Eclipse upstream bug linked.

On Mon, 2009-11-02 at 18:59 +0000, nh2 wrote:
> Workaround works for me, too.
> System -> Preferences -> Assistive Technologies -> Untick first checkbox -> Eclipse works.
>
> Do you think we should mark this as a duplicate of 445009? It really
> seems to be the same issue.
>

I think it is a good idea to mark this bug as a duplicate if it is
similar.

At the same time I think we should fix the problem in Eclipse so that we
don't have to untick first checkbox in Assistive Technologies, this so
that we don't break other programs - or that the fix is not permanent.

According to a patch in the Eclipse upstream tracker, the crash in pango_layout_new could be caused by just about any exception, which explains why the same symptom shows up for so many unrelated bugs.